International Application No. PCT/EP99/02760 was published in English on Nov. 11, 1999.
This invention relates to a weaving machine, comprising a shed-forming device provided in order in successive operating cycles to form a shed between a part of the warp threads provided on the weaving machine, a selection device provided in order in every operating cycle to select a weft thread from a number of different weft threads, and a weft thread mechanism provided in order in each case to insert and cut off the necessary length of the selected weft thread in the shed, so that a fabric is formed in which weft threads only extend over a part of the fabric width and are pattern-formingly inwoven by warp threads.
Kelim and Gobelin fabrics consist of warp threads and weft threads. The weft threads are inwoven in such a manner by the warp threads that they have running parts along the top of the fabric which cover the warp threads. These visible parts of the various weft threads together form a pattern. It is also characteristic of these fabrics that in one and the same weft line different color areas of the pattern are formed by respective weft thread parts (with a different color), which only extend over a part of the fabric width. Moreover it is typical for these fabrics (in particular for Gobelin fabrics) that the pattern consists of a great number of different colors.
In the Belgian patent no. 1004414A3 (patent application no. 9000586) a weaving machine is described which has the characteristics mentioned in the first paragraph of this specification.
The selection device of this known weaving machine comprises a color grating in which the various weft threads can be provided in several rows next to one another. This color grating can be moved both in warp direction and in weft direction in order in every operating cycle to bring (to select) a specific weft thread (in function of the pattern to be formed) to a selection position so that it can be brought into the shed by a rapier.
Since this color grating must be able to be moved according to two different, mutually perpendicular, directions, two drive devices must be provided. Such a selection device operates rather slowly and is furthermore also complex and expensive.
The purpose of this invention is to provide such a weaving machine with a selection device which does not have the above mentioned disadvantages.
This purpose is achieved according to this invention by a weaving machine with the characteristics mentioned in the first paragraph of this specification, whereby the various weft threads can be provided in one row in the selection device, and whereby the selection device comprises at least one rotatable element which is provided in order, through its rotation, to move the aforesaid row for the selection of a weft thread.
With such a selection device one single driving means is sufficient in order to rotate the rotatable element to such a position that one of the various weft threads is selected (brought into a selection position). Such a rotating driving means, such as for example an electric motor, works faster, and is also much simpler and less expensive than the two linearly moving driving means of the known weaving machine.
Another aspect of this invention relates to a method for manufacturing a fabric with pattern-forming weft threads on a weaving machine, such as for example a Kelim or Gobelin fabric, whereby in successive operating cycles a shedforming device is operated in order to form a shed between a part of the warp threads provided on the weaving machine, whereby in every operating cycle a selection device is operated in order to select a weft thread from a number of different weft threads, and whereby in every operating cycle a weft mechanism is operated in order to insert and cut off the necessary length of the selected weft thread in the shed.
The method known from the above mentioned Belgian patent, has the properties which are mentioned in the preceding paragraph of this specification, but has the disadvantage that for the selection of a weft thread two different drive devices have to be operated.
A purpose of this invention is also to provide such a method, which simplifies the operation for the selection of a weft thread.
This aim is achieved by utilizing a method according to this invention, whereby the various weft threads are provided in one row in a selection device with at least one rotatable element which is provided in order, through its rotation, to move the aforesaid row for the selection of a weft thread.
According to this m method for the selection of a weft thread only the operation of a rotating driving means is required. This is considerably simpler that the operation of two linearly moving driving means.
Moreover this invention also relates to the fabrics manufactured according to the above method, in particular Kelim and Gobelin fabrics.
In a preferred embodiment of the weaving machine according to this invention the rotatable element is provided in order move the row of weft threads according to a closed path. Because of this a rather long row of weft threads can be provided xe2x80x94whereby the row for example forms a circle xe2x80x94while every weft thread can nevertheless be brought in a fast and efficient manner into a selection position, and while the space that this row occupies remains restricted. Another advantage of this embodiment is that the rotating element for each selection can be rotated according to the same direction of rotation. By allowing the rotating element to rotate according to one direction of rotation or the other, independently of the position of the weft thread to be selected in relation to the selection position, the operating speed can still be increased.
The row of weft threads is preferably so provided that the row can be carried by at least one end less carrier, which can be rotated by the rotatable element.
The selection device and the weft mechanism of the weaving machine according to this invention are preferably provided on one and the same positioning device which can be moved in the weft direction. Because of this through the operation of one driving means both the selection device and the weft mechanism can be positioned.
This weft mechanism in a very preferred embodiment of the weaving machine also comprises a gripping means which, in relation to the aforesaid positioning device, is movable in the weft direction, while it is provided in order to carry a weft thread selected by the selection device and, through its movement in relation to the positioning device, bring it into the shed.
The weft mechanism preferably also comprises a cutting means that is provided in order to cut through the weft thread brought into the shed between the shed and the selection device.
A particular embodiment of the weaving machine according to this invention comprises a weaving reed that is provided in order to remain in a fixed position during the weaving, while the weaving machine is provided with a construction which can move back and forth in warp direction which can move back and forth the last formed fabric part together with the (parts of the) warp threads extending from this fabric part through the reed in order to beat up one or several inwoven weft threads against the already formed fabric part.
With the method according to this invention the beating-up of one or several inwoven weft threads against the already formed fabric part is also preferably performed by moving toward this reed the last formed fabric part together with the (parts of the) warp threads running from this fabric part through a reed of the weaving machine, while the reed stands still.
On a weaving machine of which the reed performs a back and forth movement in order to beat up the weft threads the space in the vicinity of the reed must remain free in order to enable the movements of the reed. The fact that the weaving machine according to this invention has a reed that can remain in a fixed position during the weaving makes it possible to dispose the selection device and the weft mechanism in an ideal location, in the vicinity of the reed.
The shed-forming device, the selection device and the weft mechanism of another very preferred embodiment of the weaving machine can be so operated that in every operating cycle a shed is automatically formed between specific warp threads, a specific weft thread is selected, and a specific length of the selected weft thread is brought into the shed, whereby these warp threads, this weft thread and this length are in each case so determined that the weft threads are inwoven by the warp threads and form a predetermined pattern in the fabric.
With the implementation of the above described method according to this invention the shed-forming device, the selection device and the weft mechanism are preferably operated in the manner mentioned in the preceding paragraph.
The weaving machine is preferably also provided with a data processing unit, and with input means for inputting pattern data into this unit which determine the pattern to be formed, while this data processing unit is provided in order to determine the operating data or operating signals from these pattern data which are required for operating the shed-forming device, the selection device and the weft mechanism.
This data processing unit can for example be a computer, into which the pattern data can be input, for example by inputting an image of the pattern to be formed via a scanner connected to the computer. It that manner the operating data which are required for manufacturing a fabric with that pattern on the weaving machine are obtained in a particularly simple and fast manner.
When utilizing the method according to this invention use will preferably be made of a weaving machine which is provided with such a data processing unitxe2x80x94such as e.g. a computerxe2x80x94, pattern data, which determine the pattern, are input into this unitxe2x80x94e.g. by means of a scannerxe2x80x94, and this unit is providedxe2x80x94e.g. programmedxe2x80x94in order to determine the operating data or operating signals from these pattern data which are required for operating the shed-forming device, the selection device and the weft mechanism.
With handmade Kelim and Gobelin fabrics every weft thread is pattern-formingly inwoven from one extremityxe2x80x94which protrudes along the bottom side of the fabricxe2x80x94by a number of successive warp threads (located one next to the other), and the weft thread after passing around the last warp thread runs back to the first warp thread, where the other extremity of the weft thread protrudes next to the first mentioned extremity along the bottom side of the fabric. Because of this gaps are visible between the neighboring pattern-forming parts of weft threads inwoven in one and the same weft line. This is considered as a typical characteristic of handmade Kelim and Gobelin fabrics.
In order to achieve this typical characteristic with the fabrics which are manufactured by utilizing the method according to this invention, every weft thread is preferably inwoven on both sides of a pattern-forming part by warp threads which are provided along the back of the fabric.
This invention will now be further explained in the following more detailed specification of the weaving machine and the method according to this invention. The characteristics of the invention presented in this specification are purely illustrative, and can in no way be interpreted as a restriction on the protection claimed for this invention in the claims.